'\" et
.TH AIO_FSYNC "3P" 2017 "IEEE/The Open Group" "POSIX Programmer's Manual"
.\"
.SH PROLOG
This manual page is part of the POSIX Programmer's Manual.
The Linux implementation of this interface may differ (consult
the corresponding Linux manual page for details of Linux behavior),
or the interface may not be implemented on Linux.
.\"
.SH NAME
aio_fsync
\(em asynchronous file synchronization
.SH SYNOPSIS
.LP
.nf
#include <aio.h>
.P
int aio_fsync(int \fIop\fP, struct aiocb *\fIaiocbp\fP);
.fi
.SH DESCRIPTION
The
\fIaio_fsync\fR()
function shall asynchronously perform a file synchronization operation,
as specified by the
.IR op
argument, for I/O operations associated with the file indicated by the
file descriptor
.IR aio_fildes
member of the
.BR aiocb
structure referenced by the
.IR aiocbp
argument and queued at the time of the call to
\fIaio_fsync\fR().
The function call shall return when the synchronization request has been
initiated or queued to the file or device (even when the data cannot be
synchronized immediately).
.P
If
.IR op
is O_DSYNC,
all currently queued I/O operations shall be completed as if by a call to
\fIfdatasync\fR();
that is, as defined for synchronized I/O data integrity completion.
.P
If
.IR op
is O_SYNC,
all currently queued I/O operations shall be completed as if by a call to
\fIfsync\fR();
that is, as defined for synchronized I/O file integrity completion.
If the
\fIaio_fsync\fR()
function fails, or if the operation queued by
\fIaio_fsync\fR()
fails, then outstanding I/O operations are not guaranteed to have been
completed.
.P
If
\fIaio_fsync\fR()
succeeds, then it is only the I/O that was queued at the time of the
call to
\fIaio_fsync\fR()
that is guaranteed to be forced to the relevant completion state. The
completion of subsequent I/O on the file descriptor is not guaranteed
to be completed in a synchronized fashion.
.P
The
.IR aiocbp
argument refers to an asynchronous I/O control block. The
.IR aiocbp
value may be used as an argument to
\fIaio_error\fR()
and
\fIaio_return\fR()
in order to determine the error status and return status, respectively,
of the asynchronous operation while it is proceeding. When the request
is queued, the error status for the operation is
.BR [EINPROGRESS] .
When all data has been successfully transferred, the error status shall
be reset to reflect the success or failure of the operation. If the
operation does not complete successfully, the error status for the
operation shall be set to indicate the error. The
.IR aio_sigevent
member determines the asynchronous notification to occur as specified
in
.IR "Section 2.4.1" ", " "Signal Generation and Delivery"
when all operations have achieved synchronized I/O completion. All
other members of the structure referenced by
.IR aiocbp
are ignored. If the control block referenced by
.IR aiocbp
becomes an illegal address prior to asynchronous I/O completion, then
the behavior is undefined.
.P
If the
\fIaio_fsync\fR()
function fails or
.IR aiocbp
indicates an error condition, data is not guaranteed to have been
successfully transferred.
.SH "RETURN VALUE"
The
\fIaio_fsync\fR()
function shall return the value 0 if the I/O operation is successfully
queued; otherwise, the function shall return the value \-1 and set
.IR errno
to indicate the error.
.SH ERRORS
The
\fIaio_fsync\fR()
function shall fail if:
.TP
.BR EAGAIN
The requested asynchronous operation was not queued due to
temporary resource limitations.
.TP
.BR EBADF
The
.IR aio_fildes
member of the
.BR aiocb
structure referenced by the
.IR aiocbp
argument is not a valid file descriptor.
.TP
.BR EINVAL
This implementation does not support synchronized I/O for this file.
.TP
.BR EINVAL
The
.IR aio_fildes
member of the
.BR aiocb
structure refers to a file on which an
\fIfsync\fR()
operation is not possible.
.TP
.BR EINVAL
A value of
.IR op
other than O_DSYNC or O_SYNC was specified, or O_DSYNC was specified and
the implementation does not provide runtime support for the Synchronized
Input and Output option, or O_SYNC was specified and the implementation
does not provide runtime support for the File Synchronization option.
.P
In the event that any of the queued I/O operations fail,
\fIaio_fsync\fR()
shall return the error condition defined for
\fIread\fR()
and
\fIwrite\fR().
The error is returned in the error status for the asynchronous operation,
which can be retrieved using
\fIaio_error\fR().
.LP
.IR "The following sections are informative."
.SH EXAMPLES
None.
.SH "APPLICATION USAGE"
Note that even if the file descriptor is not open for writing, if
there are any pending write requests on the underlying file, then
that I/O will be completed prior to the return of a call to
\fIaio_error\fR()
or
\fIaio_return\fR()
indicating that the operation has completed.
.SH RATIONALE
None.
.SH "FUTURE DIRECTIONS"
None.
.SH "SEE ALSO"
.IR "\fIaio_error\fR\^(\|)",
.IR "\fIaio_return\fR\^(\|)",
.IR "\fIfcntl\fR\^(\|)",
.IR "\fIfdatasync\fR\^(\|)",
.IR "\fIfsync\fR\^(\|)",
.IR "\fIopen\fR\^(\|)",
.IR "\fIread\fR\^(\|)",
.IR "\fIwrite\fR\^(\|)"
.P
The Base Definitions volume of POSIX.1\(hy2017,
.IR "\fB<aio.h>\fP"
.\"
.SH COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1-2017, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 7, 2018 Edition,
Copyright (C) 2018 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group.
In the event of any discrepancy between this version and the original IEEE and
The Open Group Standard, the original IEEE and The Open Group Standard
is the referee document. The original Standard can be obtained online at
http://www.opengroup.org/unix/online.html .
.PP
Any typographical or formatting errors that appear
in this page are most likely
to have been introduced during the conversion of the source files to
man page format. To report such errors, see
https://www.kernel.org/doc/man-pages/reporting_bugs.html .
